RationaleBetalactam antibiotics are the most common causes of drug hypersensitivity reported in children. Penicilloyl polylysine (PPL) and minor determinant were used for skin test but PPL is not commonly available. This study was to determine negative predictive value (NPV) of skin testing with betalactam antibiotics for diagnosis of betalactam hypersensitivity.MethodsPatients age 1-18 years old with history of betalactam hypersensitivity were evaluated by skin test (skin prick test, intradermal test) with culprit drugs (penicillin G, ampicillin, amoxicillin-clavulonic acid, cloxacillin and cephalosporin). Patients who have negative skin test were performed drug provocation test (DPT) in 3 dose graded challenge. The hypersensitivity reactions was classified into immediate and delay reactions.Results86 patients were evaluated for drug allergy. Only 18 patients (20%) were confirmed allergic to culprit drugs. 11 (61 %) of them confirmed by skin test. Among 75 patients with negative skin test were performed DPT, 7 patients (9.3%) were reacted providing NPV 90.7%. The most common culprit drug was amoxicillin (66.7%), followed by amoxicillin-clavulonic acid (16.7%). The history of immediate reaction was associated with true drug allergy (p value= 0.01). There were no serious systemic reaction in our study. There was only minor reactions which were response to symptomatic treatments.ConclusionsAmong children with history of betalactam hypersensitivity, skin testing with culprit drugs was safe and providing a good NPV when PPL was unavailable. However, skin test with betalactam antibiotics did not provide high sensitivity, thus DPT is necessary to confirm the diagnosis of drug hypersensitivity. RationaleBetalactam antibiotics are the most common causes of drug hypersensitivity reported in children. Penicilloyl polylysine (PPL) and minor determinant were used for skin test but PPL is not commonly available. This study was to determine negative predictive value (NPV) of skin testing with betalactam antibiotics for diagnosis of betalactam hypersensitivity. Betalactam antibiotics are the most common causes of drug hypersensitivity reported in children. Penicilloyl polylysine (PPL) and minor determinant were used for skin test but PPL is not commonly available. This study was to determine negative predictive value (NPV) of skin testing with betalactam antibiotics for diagnosis of betalactam hypersensitivity. MethodsPatients age 1-18 years old with history of betalactam hypersensitivity were evaluated by skin test (skin prick test, intradermal test) with culprit drugs (penicillin G, ampicillin, amoxicillin-clavulonic acid, cloxacillin and cephalosporin). Patients who have negative skin test were performed drug provocation test (DPT) in 3 dose graded challenge. The hypersensitivity reactions was classified into immediate and delay reactions. Patients age 1-18 years old with history of betalactam hypersensitivity were evaluated by skin test (skin prick test, intradermal test) with culprit drugs (penicillin G, ampicillin, amoxicillin-clavulonic acid, cloxacillin and cephalosporin). Patients who have negative skin test were performed drug provocation test (DPT) in 3 dose graded challenge. The hypersensitivity reactions was classified into immediate and delay reactions. Results86 patients were evaluated for drug allergy. Only 18 patients (20%) were confirmed allergic to culprit drugs. 11 (61 %) of them confirmed by skin test. Among 75 patients with negative skin test were performed DPT, 7 patients (9.3%) were reacted providing NPV 90.7%. The most common culprit drug was amoxicillin (66.7%), followed by amoxicillin-clavulonic acid (16.7%). The history of immediate reaction was associated with true drug allergy (p value= 0.01). There were no serious systemic reaction in our study. There was only minor reactions which were response to symptomatic treatments. 86 patients were evaluated for drug allergy. Only 18 patients (20%) were confirmed allergic to culprit drugs. 11 (61 %) of them confirmed by skin test. Among 75 patients with negative skin test were performed DPT, 7 patients (9.3%) were reacted providing NPV 90.7%. The most common culprit drug was amoxicillin (66.7%), followed by amoxicillin-clavulonic acid (16.7%). The history of immediate reaction was associated with true drug allergy (p value= 0.01). There were no serious systemic reaction in our study. There was only minor reactions which were response to symptomatic treatments. ConclusionsAmong children with history of betalactam hypersensitivity, skin testing with culprit drugs was safe and providing a good NPV when PPL was unavailable. However, skin test with betalactam antibiotics did not provide high sensitivity, thus DPT is necessary to confirm the diagnosis of drug hypersensitivity. Among children with history of betalactam hypersensitivity, skin testing with culprit drugs was safe and providing a good NPV when PPL was unavailable. However, skin test with betalactam antibiotics did not provide high sensitivity, thus DPT is necessary to confirm the diagnosis of drug hypersensitivity.